Regenerative thermal energy system and method of operating the same

ABSTRACT

A regenerative thermal energy system includes a heat exchange reactor that includes a top entry portion, a lower entry portion, and a bottom discharge portion. The system also includes at least one fluid source coupled in flow communication with the at least one heat exchange reactor at the lower entry portion. The system also includes at least one cold particle storage source coupled in flow communication with the at least one heat exchange reactor at the top entry portion. The system further includes at least one thermal energy storage (TES) vessel coupled in flow communication with the heat exchange reactor at each of the bottom discharge portion and the top entry portion. The heat exchange reactor is configured to facilitate direct contact and counter-flow heat exchange between solid particles and a fluid.

BACKGROUND

The field of the invention relates generally to energy storage and, moreparticularly, to regenerative thermal energy storage (TES) systemsassociated with adiabatic compressed air energy storage (A-CAES)systems.

At least some known A-CAES systems use expansive containments, e.g.,pressure vessels or underground caverns to store hot, compressed air.Storage facilities using man-made pressure vessels require sufficientcontainment wall strength to withstand high pressures induced bycompressed air for extended periods of time. Also, these known pressurevessels are exposed to high temperatures due to the compression of theair stored within. Therefore, some known pressure vessels are fabricatedfrom expensive metal alloys with thick walls to withstand temperaturesof approximately 450 degrees Celsius (° C.) (842 degrees Fahrenheit (°F.)). Other known containments include thick concrete walls with complexstructures to facilitate gas tightness at high pressures. Such concretewalls are typically constructed to withstand temperatures ofapproximately 100° C. (212° F.), and therefore, require an activecooling system.

Such known containments, whether man-made or natural caverns, require asignificant amount of thermal insulation to facilitate decreasing heattransfer to the local environment, thereby preserving as much thermalenergy as possible for later conversion. Therefore, due to the largevolumes required, thermal energy storage within A-CAES systems requiresa substantial capital investment to merely reduce heat transfer from thestored, compressed gases.

At least some known A-CAES systems include fixed-matrix regeneratorswithin a stand-alone vessel that includes an inventory of solid mass.The solid mass stores thermal energy as hot air is channeled over thesolid mass. Also, the solid mass releases thermal energy as cold air ischanneled over the solid mass.

However, the walls of these stand-alone vessels must provide sufficientstrength to withstand the pressures of the air channeled therethrough.Therefore, strengthening the walls will increase the capitalconstruction costs of the A-CAES systems. Also, at least some knownA-CAES systems include indirect heat transfer systems that use equipmentto facilitate substantial heat losses.

BRIEF DESCRIPTION

In one aspect, a regenerative thermal energy system is provided. Thesystem includes a heat exchange reactor that includes a top entryportion, a lower entry portion, and a bottom discharge portion. Thesystem also includes at least one fluid source coupled in flowcommunication with the at least one heat exchange reactor at the lowerentry portion. The system also includes at least one cold particlestorage source coupled in flow communication with the at least one heatexchange reactor at the top entry portion. The system further includesat least one thermal energy storage (TES) vessel coupled in flowcommunication with the heat exchange reactor at each of the bottomdischarge portion and the top entry portion. The heat exchange reactoris configured to facilitate direct contact and counter-flow heatexchange between solid particles and a fluid.

In a further aspect, a power generation facility is provided. Thefacility includes at least one power generation apparatus and at leastone regenerative thermal energy system coupled to the at least one powergeneration apparatus. The at least one regenerative thermal energysystem includes a heat exchange reactor that includes a top entryportion, a lower entry portion, and a bottom discharge portion. Thesystem also includes at least one fluid source coupled in flowcommunication with the at least one heat exchange reactor at the lowerentry portion. The system further includes at least one cold particlestorage source coupled in flow communication with the at least one heatexchange reactor at the top entry portion. The system also includes atleast one thermal energy storage (TES) vessel coupled in flowcommunication with the heat exchange reactor at each of the bottomdischarge portion and the top entry portion, wherein the heat exchangereactor is configured to facilitate direct contact and counter-flow heatexchange between solid particles and a fluid and channel hot pressurizedair to the at least one power generation apparatus.

In another aspect, a method of operating a power generation facility isprovided. The method includes channeling solid particles downwardthrough a heat exchange reactor and channeling pressurized air upwardthrough the heat exchange reactor. The method also includes transferringheat from the pressurized air to the solid particles through directcontact. The method further includes channeling the solid particles intoat least one thermal energy storage (TES) vessel.

DRAWINGS

These and other features, aspects, and advantages of the presentinvention will become better understood when the following detaileddescription is read with reference to the accompanying drawings in whichlike characters represent like parts throughout the drawings, wherein:

FIG. 1 is a schematic view of a first portion of an exemplaryregenerative thermal energy system.

FIG. 2 is a flow chart of a method of charging the regenerative thermalenergy system shown in FIG. 1.

FIG. 3 is a schematic view of a second portion of the regenerativethermal energy system partially shown in FIG. 1.

FIG. 4 is a flow chart of a method of discharging the regenerativethermal energy system shown in FIG. 3.

FIG. 5 is a schematic view of an exemplary power generation facilitythat uses the regenerative thermal energy system shown in FIGS. 1 and 3.

Unless otherwise indicated, the drawings provided herein are meant toillustrate key inventive features of the invention. These key inventivefeatures are believed to be applicable in a wide variety of systemscomprising one or more embodiments of the invention. As such, thedrawings are not meant to include all conventional features known bythose of ordinary skill in the art to be required for the practice ofthe invention.

DETAILED DESCRIPTION

In the following specification and the claims, reference will be made toa number of terms, which shall be defined to have the followingmeanings.

The singular forms “a”, “an”, and “the” include plural references unlessthe context clearly dictates otherwise.

“Optional” or “optionally” means that the subsequently described eventor circumstance may or may not occur, and that the description includesinstances where the event occurs and instances where it does not.

Approximating language, as used herein throughout the specification andclaims, may be applied to modify any quantitative representation thatcould permissibly vary without resulting in a change in the basicfunction to which it is related. Accordingly, a value modified by a termor terms, such as “about” and “substantially”, are not to be limited tothe precise value specified. In at least some instances, theapproximating language may correspond to the precision of an instrumentfor measuring the value. Here and throughout the specification andclaims, range limitations may be combined and/or interchanged, suchranges are identified and include all the sub-ranges contained thereinunless context or language indicates otherwise.

FIG. 1 is a schematic view of a first portion 102 of an exemplaryregenerative thermal energy system 100. First portion 102 includes thecomponents of system 100 used during a charging operation, i.e., when asolid mass (described further below) is charged with thermal energy forstorage.

In the exemplary embodiment, regenerative thermal energy system 100includes a heat exchange reactor 110 including a plurality of walls 112that define a fully enclosed heat transfer cavity 114. Walls 112 alsodefine a top entry portion 116 coupled in flow communication with atleast one cold particle storage source 118. Cold particle storage source118 is any containment and delivery system that enables operation ofregenerative thermal energy system 100 as described herein, including,without limitation, hoppers, bins, silos, solids transfer devices, andgravity-feed devices. Storage source 118 and top entry portion 116cooperate to inject small, cold, solid particles 119 into heat transfercavity 114. Particles 119 are any solids that enable operation ofregenerative thermal energy system 100 as described herein, including,without limitation, sand.

Also, in the exemplary embodiment, walls 112 define a lower entryportion 120 that is coupled in flow communication with at least onefluid source, i.e., an air compressor 122, e.g., without limitation, amulti-stage air compressor. Alternatively, any fluid, including liquidand gas, that enables operation of regenerative thermal energy system100 as described herein is used. Also, alternatively, system 100includes a staged air compression system (not shown) with a plurality ofair compressors 122 coupled in series. Further, alternatively, lowerentry portion 120 defines a plurality of air inlet ports (not shown)that may be coupled to an air inlet manifold (not shown). Air compressor122 is coupled to an electric motor 124. Alternatively, air compressor122 is driven by any mechanism that enables operation of regenerativethermal energy system 100 as described herein, including, withoutlimitation, a steam turbine, a gas turbine, a water turbine, a windturbine, a gasoline combustion engine, and a diesel engine, all withgeared couplings as necessary. Air compressor 122 is configured toreceive cold, ambient air 126 and discharge hot, compressed air 128 intoheat transfer cavity 114, as described further below.

In the exemplary embodiment, regenerative thermal energy system 100includes moisture removal apparatus configured to remove moisture fromcompressed air prior to injection of hot, compressed air 128 into heattransfer cavity 114. Such moisture removal apparatus includes at leastone of an upstream moisture separator 123 coupled in flow communicationwith air compressor 122 upstream of air compressor 122, downstreammoisture separator 125 coupled in flow communication with air compressor122 downstream of air compressor 122, and a plurality of interstagemoisture separators 127 within air compressor 122. Each of upstreammoisture separator 123, downstream moisture separator 125, andinterstage moisture separators 127 facilitate removal of water 129 fromthe air.

Further, in the exemplary embodiment, walls 112 define an inwardlyinclined bottom discharge portion 130 configured to facilitate storageof hot solid particles 132. Bottom discharge portion 130 is alsoconfigured to facilitate discharge of hot solid particles 132 out ofheat transfer cavity 114 with the assistance of gravity.

Moreover, in the exemplary embodiment, regenerative thermal energysystem 100 includes at least one cyclone filter 140 coupled in flowcommunication with heat transfer cavity 114 through an air extractionconduit 142. Conduit 142 is positioned between top entry portion 116 andlower entry portion 120, and is configured to direct cold, pressurizedair 144 and entrained particles 146 from heat transfer cavity 114 tocyclone filter 140. At least one cold, pressurized air storage vessel148 is coupled in flow communication with cyclone filter 140. Also,cyclone filter 140 includes a sloped portion 150 configured to retainentrained particles 146. Storage source 118 is coupled in flowcommunication with sloped portion 150.

Also, in the exemplary embodiment, regenerative thermal energy system100 includes at least one thermal energy storage (TES) vessel 160coupled in flow communication with heat exchange reactor 110 at bottomdischarge portion 130. TES vessel 160 defines a particle storage cavity162 configured to receive and store hot solid particles 132 therein.Cavity 162 is sufficiently sized to enable operation of regenerativethermal energy system 100 through one full cycle as described herein.TES vessel 160 includes an insulation layer 164 that is sufficient toenable maintaining hot solid particles 132 within a predeterminedtemperature range through one full cycle of regenerative thermal energysystem 100 as described herein. For example, and without limitation,insulation layer 164 facilitates maintaining hot solid particles 132within the predetermined temperature range for 12 to 24 hours. TESvessel 160 is configured to operate at approximately atmosphericpressure.

Further, in the exemplary embodiment, regenerative thermal energy system100 includes at least one solids transfer pump 166 coupled in flowcommunication with TES vessel 160. Pump 166 is configured to transferhot particles 168 from TES vessel 160 as described further below. In theexemplary embodiment, solids transfer pump 166 is a GE Posimetric® pumpcommercially available from GE Energy, Atlanta, Ga., USA. Alternatively,any pumping device that enables operation of regenerative thermal energysystem 100 as described herein is used.

Also, in the exemplary embodiment, regenerative thermal energy system100 includes at least one device configured to increase a residence timeof solid particles 119 and hot, compressed air 128. For example, withoutlimitation, a plurality of air and particle deflector devices 163 arecoupled to walls 112 within heat transfer cavity 114 and extend inwardtherefrom. Also, for example, and without limitation, air and particledeflector devices 163 and walls 112 define a tortuous heat transferchannel 165. Further, for example, and without limitation, heat transferprojections 167, e.g., without limitation, heat fins, are positionedwithin channel 165. Deflector devices 163, channel 165, and projections167 facilitate increasing the residence time to further facilitate heattransfer between particles 119 and air 128.

FIG. 2 is a flow chart of a method 200 of charging regenerative thermalenergy system 100 (shown in FIG. 1). During the charging operation,small, cold, solid particles 119 (shown in FIG. 1) are injected 202 intoheat transfer cavity 114 from storage source 118 through top entryportion 116 (all shown in FIG. 1). Particles 119 are injected within atemperature range between approximately 0 degrees Celsius (° C.) (32degrees Fahrenheit (° F.)) and approximately 49° C. (120° F.).Alternatively, particles 119 are injected within any temperature rangethat enables operation of regenerative thermal energy system 100 asdescribed herein. Particles 119 are injected at any pressures thatenable operation of regenerative thermal energy system 100 as describedherein.

Also, during the charging operation, particles 119 are directed 204downward through heat exchange reactor 110 (shown in FIG. 1) with theassistance of gravity. Cold, ambient air 126 (shown in FIG. 1) isreceived and compressed 206 by air compressor 122 (shown in FIG. 1).Ambient air 126 is in a temperature range between approximately 0° C.(32° F.) and approximately 49° C. (120° F.), and has an atmosphericpressure of approximately one atmosphere, i.e., 1.015 bar, 101.353kilo-Pascal (kPa), and 14.7 pounds per square inch (psi). Alternatively,inlet air 126 to air compressor 122 has temperatures and pressures inany range that enables operation of regenerative thermal energy system100 as described herein.

Further, during the charging operation, air compressor 122 discharges208 hot, compressed air 128 (shown in FIG. 1) into heat transfer cavity114 with a temperature range between approximately 250° C. (482° F.) andapproximately 700° C. (1292° F.), and a pressure range betweenapproximately 20 bar (2000 kPa, 290 psi) and approximately 70 bar (7000kPa, 1015 psi). Alternatively, hot, compressed air 128 discharged fromair compressor 122 has temperatures and pressures in any range thatenables operation of regenerative thermal energy system 100 as describedherein. Hot, compressed air 128 is channeled 210 upward through heattransfer cavity 114.

Moreover, during the charging operation, since particles 119 and air 128flow counter to each other, particles 119 and air 128 come into directcontact with each other within heat transfer cavity 114. Such directcontact between air 128 and particles 119 facilitates heat exchangetherebetween such that air 128 transfers 212 thermal energy to particles119. The heat exchange generates hot solid particles 132, cold,pressurized air 144, and entrained particles 146 (all shown in FIG. 1).Deflector devices 163, channel 165, and projections 167 facilitateincreasing the residence time to further facilitate heat transferbetween particles 119 and air 128.

Also, during the charging operation, cold, pressurized air 144 andentrained particles 146 are extracted 214 from heat transfer cavity 114to cyclone filter 140 that uses cyclonic action to separate 216 air 144from particles 146. Air 144 is directed 218 to at least one cold,pressurized air storage vessel 148. Air 144 has a temperature valuewithin a range between approximately 20° C. (68° F.) and 60° C. (140°F.) and within a pressure range between approximately 20 bar (2000 kPa,290 psi) and approximately 70 bar (7000 kPa, 1015 psi). Alternatively,air 144 is within any temperature range that enables operation ofregenerative thermal energy system 100 as described herein.

Further, during the charging operation, entrained particles 146 aredirected 220 downward through cyclone filter 140 with the assistance ofgravity and are stored at sloped portion 150 (shown in FIG. 1) ofcyclone filter 140. Particles 146 have a temperature value within arange between approximately 20° C. (68° F.) and approximately 60° C.(140° F.). Alternatively, particles 146 are within any temperature rangethat enables operation of regenerative thermal energy system 100 asdescribed herein. Particles 146 are channeled to cold particle storagesource 118 for regenerative use.

Moreover, during the charging operation, hot solid particles 132 aredeposited at inwardly inclined bottom discharge portion 130. Hot solidparticles 132 are transferred 222 out of heat transfer cavity 114 to TESvessel 160 with the assistance of gravity. TES vessel 160 receives andstores hot solid particles 132 within particle storage cavity 162. Hotsolid particles 132 are maintained 224 within a predeterminedtemperature range between approximately 240° C. (464° F.) andapproximately 690° C. (1274° F.) through one full cycle of regenerativethermal energy system 100 as described herein. For example, and withoutlimitation, hot solid particles 132 are maintained within the exemplarytemperature range for approximately 12 to approximately 24 hours. TESvessel 160 is maintained at approximately atmospheric pressure.

FIG. 3 is a schematic view of a second portion 170 of regenerativethermal energy system 100. Second portion 170 includes the components ofsystem 100 used during a discharging operation, i.e., when thermalenergy stored within a hot solid mass (described further below) isliberated to generate power. Many of the same components of system 100used in first portion 102 (shown in FIG. 1) for charging operationsdescribed above are also used for discharging operations.

As described above, in the exemplary embodiment, regenerative thermalenergy system 100 includes at least one solids transfer pump 166 coupledin flow communication with TES vessel 160. Solids transfer pump 166 isalso coupled in flow communication with heat transfer cavity 114 of heatexchange reactor 110 through top entry portion 116. Solids transfer pump166 is configured to transfer hot particles 168 from TES vessel 160 intoheat transfer cavity 114.

Also, as described above, stored, cold, pressurized air 144 is containedin air storage vessel 148 within a pressure range between approximately20 bar (2000 kPa, 290 psi) and approximately 70 bar (7000 kPa, 1015psi). Therefore, solids transfer pump 166 is configured to injectparticles 168 into heat exchange reactor 110 with sufficient pressure toovercome the pressure of air 144.

Further, as described above, cyclone filter 140 is coupled in flowcommunication with heat transfer cavity 114 through air extractionconduit 142. Cyclone filter 140 is further coupled in flow communicationwith heat transfer cavity 114 through an entrained particle returnconduit 175.

Moreover, in the exemplary embodiment, regenerative thermal energysystem 100 includes at least one expander 180 rotatably coupled to amachine, e.g., without limitation, a generator 182. Expander 180 iscoupled in flow communication with cyclone filter 140.

In at least some alternative embodiments, regenerative thermal energysystem 100 includes at least one combustion apparatus 181 coupled inflow communication with cyclone filter 140 and expander 180. Combustionapparatus 181 includes a hot air extension line 183 coupled to cyclonefilter 140. Combustion apparatus 181 also includes a fuel line 185.Combustion apparatus 181 further includes an air/fuel mixer 186 coupledto hot air extension line 183 and fuel line 185. Combustion apparatus181 also includes a combustion chamber 187 coupled to air/fuel mixer 186and hot air extension line 183. Combustion apparatus 181 furtherincludes a heat exchange device 188 coupled to combustion chamber 187,hot air extension line 183, and expander 180. Combustion apparatus 181further includes an exhaust conduit 189 coupled to heat exchange device188.

FIG. 4 is a flow chart of a method 300 of discharging regenerativethermal energy system 100 (shown in FIG. 3). During the dischargingoperation, hot solid particles 132 (shown in FIG. 3) are maintained 302within a predetermined temperature range between approximately 240° C.(464° F.) and approximately 690° C. (1274° F.) through one full cycle ofregenerative thermal energy system 100 as described herein. For example,and without limitation, hot solid particles 132 are maintained withinthe exemplary temperature range for 12 to 24 hours. TES vessel 160(shown in FIG. 3) is maintained at approximately atmospheric pressure.Hot particles 168 (shown in FIG. 3) are transferred from TES vessel 160into heat transfer cavity 114 (shown in FIG. 3) through top entryportion 116 (shown in FIG. 3) within a similar temperature range.

Also, during the discharging operation, and as described above, cold,pressurized air 144 is contained 304 in air storage vessel 148 (shown inFIG. 3). Air 144 has a temperature value within a range betweenapproximately 20° C. (68° F.) and 60° C. (140° F.) and within a pressurerange between approximately 20 bar (2000 kPa, 290 psi) and approximately70 bar (7000 kPa, 1015 psi). Stored, cold, pressurized air 144 isdischarged 306 into heat transfer cavity 114. Air 144 is directed 308upward through heat transfer cavity 114. Solids transfer pump 166 (shownin FIG. 3) injects 310 particles 168 into heat exchange reactor 110 withsufficient pressure to overcome the pressure of air 144.

Further, during the discharging operation, since particles 168 and air144 flow counter to each other, particles 168 and air 144 come intodirect contact with each other within heat transfer cavity 114. Suchdirect contact between air 144 and particles 168 facilitates heatexchange therebetween such that particles 168 transfers 312 thermalenergy to air 144. The heat exchange generates hot, pressurized air 172,entrained particles 174, and cold particles 190 (all shown in FIG. 3).

Moreover, during the discharging operation, hot, pressurized air 172 andentrained particles 174 are extracted 314 from heat transfer cavity 114to cyclone filter 140 (shown in FIG. 3) that uses cyclonic action toseparate 316 air 172 from particles 174. Hot, pressurized air 172 andentrained particles 174 are within a temperature range of approximately240° C. (464° F.) and approximately 690° C. (1274° F.).

Also, during the discharging operation, entrained particles 174 aredirected 318 downward through cyclone filter 140 with the assistance ofgravity and are stored at sloped portion 150 (shown in FIG. 3) ofcyclone filter 140. Some reusable, i.e., still transferable, thermalenergy may reside within particles 174. Therefore, such particles 174within a temperature range between approximately 240° C. (464° F.) andapproximately 690° C. (1274° F.) are reinjected 320 into heat transfercavity 114 for further thermal energy transfer to air 144.Alternatively, particles 174 are reinjected into heat transfer cavity114 within any temperature range that enables operation of regenerativethermal energy system 100 as described herein. As the temperatures ofparticles 174 attains a value within a predetermined range betweenapproximately 20° C. (68° F.) and approximately 60° C. (140° F.),particles 174 are transferred 322 to cold particle storage source 118for regenerative use. Alternatively, particles 174 are channeled to coldparticle storage source 118 within any temperature range that enablesoperation of regenerative thermal energy system 100 as described herein.

Further, during the discharging operation, some cold particles 190 thathave been substantially exhausted of transferrable thermal energy aredeposited at inwardly inclined bottom discharge portion 130 (shown inFIG. 3). Particles 190 are transferred 324, with the assistance ofgravity, out of heat transfer cavity 114 to TES vessel 160 in a mannerthat reduces a probability of cannibalizing thermal energy stored in hotparticles 132. TES vessel 160 receives and stores cold particles 190within particle storage cavity 162. Cold particles 190 are transferred326 to cold particle storage source 118 for regenerative use.

Moreover, during the discharging operation, hot, pressurized air 172having a temperature value within a range between approximately 240° C.(464° F.) and approximately 690° C. (1274° F.) and within a pressurerange between approximately 20 bar (2000 kPa, 290 psi) and approximately70 bar (7000 kPa, 1015 psi) is directed 328 to expander 180 (shown inFIG. 3). Alternatively, air 172 is within any temperature range and anypressure range that enables operation of regenerative thermal energysystem 100 as described herein. Expander 180 (shown in FIG. 3) drives330 generator 182 (shown in FIG. 3) and expended air 184 (shown in FIG.3) is discharged to any place that enables operation of regenerativethermal energy system 100 as described herein.

In at least some alternative embodiments, the hot air from cyclonefilter 140 is channeled to combustion apparatus 181 through conduit 183.Some of the hot air and fuel are channeled to air/fuel mixer 186 throughconduit 183 and fuel line 185, respectively, where they are mixed. Theair/fuel mixture is channeled to combustion chamber 187 and additionalhot air in injected into combustion chamber 187 from conduit 183. Hotgases are generated and are channeled to heat exchange device 188. Heattransfer from the gases to hot air channeled from conduit 183 furtherincreases the temperature of air 172 prior to expander 180. Thecombustion gases are channeled through exhaust conduit 189

FIG. 5 is a schematic view of an exemplary power generation facility 500that uses regenerative thermal energy system 100. In the exemplaryembodiment, power generation facility 500 includes a plurality of powergenerators 502, including, without limitation, steam turbine generators,gas turbine generators, water turbine generators, wind turbinegenerators, gasoline combustion engine-driven generators, and dieselengine generators, and any combination thereof.

One example, without limitation, of operating power generation facility500 includes storing thermal energy during non-peak periods andexpending the stored thermal energy during peak periods. Duringnon-peaking generation periods, an own/operator of power generationfacility anticipates a need for additional power generation during afuture peaking period. Power generators 502 transmit electric power toelectric motors 124 of air compressors 122 (shown in FIG. 1) and thermalenergy is stored in regenerative thermal energy system 100 as describedabove. During peaking periods, regenerative thermal energy system 100substantially recovers the stored thermal energy and electric power thatis generated by generators 182 is added to the electric power generatedby power generators 502 for transmission. Such regenerative operation,including a charging and discharging operations, represents a full cycleof regenerative thermal energy system 100. As an example, withoutlimitation, such cycles may occur twice on weekdays, i.e., dischargingoperations are performed between approximately 5:00 AM and approximately9:00 AM, and again approximately 5:00 PM and approximately 10:00 PM.Charging operations are performed between those two time periods whendischarging operations are not in progress. Alternatively, someembodiments of power generation facility 500 may include multipleiterations of regenerative thermal energy system 100 such that onesystem 100 is charging and feeding a second system 100 that isdischarging.

The above-described regenerative thermal energy system provides acost-effective method for generating and storing thermal energy forlater use. The embodiments described herein facilitate storing thermalenergy in a thermal energy storage vessel during low power usage periodsfor future use during peak power usage periods. Specifically, thedevices, systems, and methods described herein facilitate transferringheat from hot compressed air to and the assistance of gravity small,cold, solid particles through direct contact. More specifically, thedevices, systems, and methods described herein facilitate using a powergeneration facility to use at least some of the power generated thereinto drive air compressors during low power usage periods. The thermalenergy now contained in the hot, small particles is stored with theparticles in an insulated vessel configured to maintain the particleswithin a specific temperature range for a certain period of time atatmospheric pressure. The cold, pressurized air is channeled to astorage vessel. During periods of high power usage, the hot particlesare channeled to mix with the stored, cold, pressurized air to transferthe thermal energy back into the air. The reheated air is channeled toan expander coupled to a generator. Therefore, since the small hotparticles are stored in a smaller vessel than that use to store the air,use of more robust structural materials and insulation for air storageis no longer required. Moreover, since the particles and air are indirect contact, equipment necessary to facilitate indirect thermalenergy transfer is not required.

An exemplary technical effect of the methods, systems, and apparatusdescribed herein includes at least one of: (a) decreasing the volume ofa vessel used to store thermal energy; and (b) directly contacting coldparticles with hot air and hot particles with cold air to regenerativelytransfer thermal energy therebetween.

Exemplary embodiments of regenerative thermal energy system for powergeneration facilities and methods for operating are described above indetail. The regenerative thermal energy system, power generationfacilities, and methods of operating such systems and facilities are notlimited to the specific embodiments described herein, but rather,components of systems and/or steps of the methods may be utilizedindependently and separately from other components and/or stepsdescribed herein. For example, the methods may also be used incombination with other systems requiring thermal energy storage andmethods, and are not limited to practice with only the regenerativethermal energy system, power generation facilities, and methods asdescribed herein. Rather, the exemplary embodiment can be implementedand utilized in connection with many other thermal energy storage andtransfer applications.

Although specific features of various embodiments of the invention maybe shown in some drawings and not in others, this is for convenienceonly. In accordance with the principles of the invention, any feature ofa drawing may be referenced and/or claimed in combination with anyfeature of any other drawing.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal language of the claims.

What is claimed is:
 1. A regenerative thermal energy system comprising:a heat exchange reactor comprising a top entry portion, a lower entryportion, and a bottom discharge portion; at least one fluid sourcecoupled in flow communication with said at least one heat exchangereactor at said lower entry portion; at least one cold particle storagesource coupled in flow communication with said at least one heatexchange reactor at said top entry portion; and at least one thermalenergy storage (TES) vessel coupled in flow communication with said heatexchange reactor at each of said bottom discharge portion and said topentry portion, wherein said heat exchange reactor is configured tofacilitate direct contact and counter-flow heat exchange between solidparticles and a fluid.
 2. A regenerative thermal energy system inaccordance with claim 1, wherein said at least one fluid sourcecomprises at least one fluid compressor and at least one fluid storagesource, wherein said at least one fluid compressor is configured tochannel fluid at a first temperature into said heat exchange reactor andsaid at least one fluid storage source is configured to channel fluid ata second temperature into said heat exchange reactor, wherein the firsttemperature is greater than the second temperature.
 3. A regenerativethermal energy system in accordance with claim 2 further comprising atleast some moisture removal apparatus comprising at least one of: atleast one moisture removal apparatus coupled in flow communication withsaid at least one fluid compressor upstream of said at least one fluidcompressor; at least one moisture removal apparatus coupled in flowcommunication with said at least one fluid compressor downstream of saidat least one fluid compressor; and at least one interstage moistureremoval apparatus within said at least one fluid compressor.
 4. Aregenerative thermal energy system in accordance with claim 1 furthercomprising at least one solids transfer pump coupled in flowcommunication with said at least one TES vessel and said top entryportion of said heat exchange reactor.
 5. A regenerative thermal energysystem in accordance with claim 1 further comprising at least onecyclone filter coupled in flow communication with said heat exchangereactor between said top entry portion and said lower entry portion,wherein said at least one cyclone filter is configured to receive fluidexiting said heat exchange reactor and solid particles entrainedtherein.
 6. A regenerative thermal energy system in accordance withclaim 5, wherein said at least one cyclone filter is further coupled inflow communication with said at least one cold particle storage source.7. A regenerative thermal energy system in accordance with claim 1,wherein said at least one TES vessel comprises at least some insulationand is configured to contain solid particles within a predeterminedrange of temperatures for a predetermined period of time.
 8. Aregenerative thermal energy system in accordance with claim 1, whereinsaid at least one heat exchange reactor defines a heat transfer cavitytherein that is configured to facilitate the direct contact and thecounter-flow heat exchange between the solid particles and the fluid,said heat transfer cavity at least partially encloses at least onedevice configured to increase a residence time of the solid particlesand the fluid, said at least one device comprises at least one of: atleast one fluid and particle deflector device; at least one heattransfer projection; and at least one heat transfer channel.
 9. A powergeneration facility comprising: at least one power generation apparatus;and at least one regenerative thermal energy system coupled to said atleast one power generation apparatus, said at least one regenerativethermal energy system comprising: a heat exchange reactor comprising atop entry portion, a lower entry portion, and a bottom dischargeportion; at least one fluid source coupled in flow communication withsaid at least one heat exchange reactor at said lower entry portion; atleast one cold particle storage source coupled in flow communicationwith said at least one heat exchange reactor at said top entry portion;and at least one thermal energy storage (TES) vessel coupled in flowcommunication with said heat exchange reactor at each of said bottomdischarge portion and said top entry portion, wherein said heat exchangereactor is configured to facilitate direct contact and counter-flow heatexchange between solid particles and a fluid and channel hot pressurizedair to said at least one power generation apparatus.
 10. A powergeneration facility in accordance with claim 9, wherein said at leastone fluid source comprises at least one fluid compressor and at leastone fluid storage source, wherein said at least one fluid compressor isconfigured to channel fluid at a first temperature into said heatexchange reactor and said at least one fluid storage source isconfigured to channel fluid at a second temperature into said heatexchange reactor, wherein the first temperature is greater than thesecond temperature.
 11. A power generation facility in accordance withclaim 9 further comprising at least one cyclone filter coupled in flowcommunication with said heat exchange reactor between said top entryportion and said lower entry portion, wherein said at least one cyclonefilter is configured to receive fluid exiting said heat exchange reactorand solid particles entrained therein.
 12. A power generation facilityin accordance with claim 11, wherein said at least one cyclone filter isfurther coupled in flow communication with said at least one coldparticle storage source and said at least one power generationapparatus.
 13. A power generation facility in accordance with claim 9,wherein said at least one TES vessel comprises at least some insulationand is configured to contain solid particles within a predeterminedrange of temperatures for a predetermined period of time.
 14. A powergeneration facility in accordance with claim 9 further comprising atleast one combustion apparatus coupled in flow communication with saidat least one cyclone filter and said at least one power generationapparatus.
 15. A method of operating a power generation facility, saidmethod comprising: channeling solid particles downward through a heatexchange reactor; channeling pressurized air upward through the heatexchange reactor; transferring heat from the pressurized air to thesolid particles through direct contact; and channeling the solidparticles into at least one thermal energy storage (TES) vessel.
 16. Themethod in accordance with claim 15 further comprising: channeling thesolid particles from the TES vessel downward through the heat exchangereactor; channeling pressurized air upward through the heat exchangereactor; transferring heat from the solid particles to the pressurizedair through direct contact; and channeling the pressurized air to atleast one power generation apparatus.
 17. The method in accordance withclaim 15, wherein channeling solid particles downward through a heatexchange reactor comprises injecting the solid particles at the top ofthe heat exchange reactor and channeling the solid particles downwardwith the assistance of gravity.
 18. The method in accordance with claim15, wherein channeling pressurized air upward through the heat exchangereactor comprises channeling the air through a cyclone filter to removeat least a portion of solid particles entrained therein.
 19. The methodin accordance with claim 15, wherein channeling the solid particles intoat least one thermal energy storage (TES) vessel comprises containingthe solid particles within a predetermined temperature range for apredetermined period of time.
 20. The method in accordance with claim 15further comprising: wherein: operating the heat exchange reactor at afirst pressure; and operating the at least one TES vessel at a secondpressure, wherein the first pressure is greater than the secondpressure, and the second pressure has a value that is approximatelyatmospheric pressure.